Decontamination of toxic chemical agents

ABSTRACT

A process of decontaminating a surface contaminated with a toxic chemical agent in which there is applied to the contaminated surface, a macroporous cross-linked hydrophobic copolymer containing an agent which is a decontaminant for the toxic chemical agent present on the surface. The decontaminant can be a chemical neutralizer such as sodium hydroxide; lithium hydroxide; concentrated bleach; and mixtures of diethylene triamine, 2-methoxy ethanol, and sodium hydroxide, for example.

BACKGROUND OF THE INVENTION

This invention relates to the decontamination of toxic chemical agentsin which a decontaminating agent is entrapped within a macroporouscross-linked copolymer. The copolymer is a powder which is a complexstructure consisting of unit particles, agglomerates, and aggregates.

The concept of producing spheres or beads by means of suspensionpolymerization techniques is well known in the Prior art. An exemplaryone of such processes is disclosed in U.S. Pat. No. 2,809,943, issuedOct. 15, 1957. However, it was found that when a material was addedwhich is a solvent for the monomers but acts as a precipitant for theresulting Polymer, a novel form of bead was provided containing anetwork of microscopic channels. This discovery is set forth in U.S.Pat. No. 4,224,415, filed July 18, 1958, issuing some twenty-two yearslater on Sept. 23, 1980. In this patent, beads are produced ranging insize from about 350 to about 1200 microns. Typical monomers includedivinyl toluene, diallyl maleate, and triallyl phosphate. Theprecipitant employed is an alkane, acid ester, or alcohol.

This technology was expanded and the precipitant was variously describedin the Patent literature as a diluent, porogen, active ingredient,solvent, functional material, and volatile agent. For example, in U.S.Reissue Pat. No. 27.026, issued Jan. 12, 1971, porous beads of adiameter less than ten microns are disclosed. Among the monomers used toproduce the beads are ethyl methacrylate, divinyl benzene, and ethyleneglycol dimethacrylate. In U.S. Pat. No. 3,418,262, issued Dec. 24, 1968,there is described a bead characterized as having a rigid spongestructure, and wherein the porogenic agent employed is an acid such asstearic acid. Intermediates in bead form were produced in U.S. Pat. No.3,509,078. issued Apr. 28, 1970, using polymeric materials such aspolyethylene glycols as the precipitant material during the in sitususpension polymerization process. The macroporous character of suchbead construction is graphically portrayed and illustrated in FIG. 1 ofU.S. Pat. No. 3,627,708, issued Dec. 14, 1971. Beads termed "pearls" areproduced, and containing active ingredients therein such as water orvarious alcohol ethers. The pearls are crosslinked to the extent ofabout twenty percent. In U.S. Pat. No. 3,637,535, issued Jan. 25, 1972,heads with a sponge structure are said to be capable of being compressedto an imperceptible powder. These beads are capable of being loaded withas much as 200-300% of active ingredients such as white spirit, andbenzin. A rigid porous bead of a trifunctional methacrylate is taught inU.S. Pat. No. 3,767,600, issued Oct. 23, 1973. Such beads have a size of10-900 microns, and various other monomers which can be employed includediacetone acrylamide, and ethylhexyl, hydroxyethyl, and hydroxypropylmethacrylates. Paraffin wax in an amount of 5-100% is used to form themicroscopic network of channels in U.S. Pat. No. 3,989,649, issued Nov.2, 1976. The wax may be removed from the bead structure by solventextraction.

While many of the foregoing U.S. patents relate to ion exchangetechnology, a bead similar to those previously described is employed asa carrier for enzymes in U.S. Pat. No. 4,208,309, issued June 17, 1980.Such beads are of the size of about 0.1 mm. U.S. Pat. No. 4,661,327,issued Apr. 28, 1987, describes a macroreticular bead containing amagnetic core. The use of hard crosslinked porous polymeric beads incosmetics as carriers is taught in U.S. Pat. No. 4,724,240, issued Feb.9, 1988, wherein various emollients and moisturizers are entrappedtherein. These beads are said to be capable of entrapping materials suchas 2-ethylhexyl oxystearate, arachidyl propionate, petroleum jelly,mineral oil, lanolin, and various siloxanes. The size of the beadsranges from 1-3,000 microns. Typical monomers include ethylene glycoldimethacrylate, lauryl methacrylate, trimethylol propanetrimethacrylate, and dipentaerythritol dimethacrylate. "In situ"hydrophobic powders and "in situ" beads may be Produced in accordancewith the teaching of this patent. Beads having a rigid sponge structureare also described in U.S. Pat. No. 4,690,825, issued Sept. 1, 1987, andwherein the beads function as a delivery vehicle for a host of materialsincluding pigments, vitamins, fragrances, drugs, repellants, detergents,and sunscreens. The beads have a size of 10-100 microns and arepreferably of a monomer system of styrene-divinyl benzene. Crosslinkingis said to range from 10-40 percent. U.S. Pat. No. 4,806,360, issuedFeb. 21, 1989, describes a post adsorbent bead which contains a melaninpigment for use as a sunscreen.

The foreign patent literature includes West German OffenlegungsschriftNo. P-2608533.6, published Sept. 30, 1976, and wherein porous polymericbeads produced by "in situ" suspension polymerization are provided, andwhich are adapted to release perfumes. A controlled release of thefragrance is disclosed, providing utility for such beads in the home,automobiles, airplanes, railway cars, hospitals, classrooms, conferencecenters, and gymnasiums. Canadian Patent No. 1,168,157, issued May 29,1984, describes hard, discrete, free flowing, bead constructions inwhich the beads entrap a series of functional materials which can beincorporated into toilet soap, body powder, and antiperspirant sticks.The Canadian Patent, it is noted, is the equivalent of European PatentNo. 61,701, issued on July 16, 1986, both of which are foreignequivalents of the parent case of the '240 patent. In EuropeanInternational Publication No. 0252463A2, published Jan. 13, 1988, thereis disclosed a bead having a hydrophobic polymer lattice, and whichentraps numerous non-cosmetic materials such as pesticides,pharmaoeuticals, pheromones, and various categories of chemicals.Steroids are entrapped, for example, in the porous beads of PCTInternational Publication No. WO-88/01164, published on Feb. 25, 1988.The steroids are adrenocortical steroids or various anti-inflammatorytype steroids. It should therefore be apparent that what began as asimple ion exchange bead concept has rapidly grown into a technology ofwidely varied application.

In accordance with the present invention, copolymer powders are producedby novel processes not believed to be taught in the prior art, asexemplified by the foregoing patents. Those patents, in general, relateto suspension polymerization processes for the production of porouspolymeric and copolymeric spheres and beads in which the precipitant ispresent during polymerization. These are defined as an "in situ"process. For example, U.S. Pat. No. 4,724,240, discloses beads andspheres produced by "in situ" suspension polymerization techniques. ThePCT International Publication, while a suspension polymerization system,can also be defined as a "post adsorption" process in its use. In thisvariance, a volatile porogen is included which may be removed byextraction and evaporation, resulting in empty beads. The beads can beloaded with diverse active ingredients, as desired, at subsequent times.A similar process is disclosed in U.S. Pat. No. 4,806,360. "Postadsorption" techniques are more attractive because of the flexibility inthe selection of active ingredients that can be subsequently entrapped,whereas in the conventional "in situ" systems, the porogen polymerized"in situ" remains in the final product.

Thus, according to the prior art, hydrophobic crosslinked porouscopolymers in particle form can be produced by at least three distinctprocesses. One process produces beads by "in situ" suspensionpolymerization, and this process is shown in Example 4 of the '240patent, and in U.S. Pat. No. 4,690,825. Another process produces beadsby suspension polymerization but the beads are "post adsorbed" with anactive ingredient after the volatile porogen is removed. This process isshown in U.S. Pat. No. 4,806.360, and in the PCT InternationalPublication. In a third process, powders are produced by "in situ"precipitation polymerization, and this process is shown in Examples 1-3of the '240 patent.

What has been accomplished in accordance with the present invention,however, is a unique concept differing from all of the foregoingmethods, and wherein post adsorbent powders are produced and employed ina novel fashion in decontaminating surfaces contaminated with toxicchemical agents. Toxic chemical agents are chemical substances ingaseous, liquid, or solid form, intended to produce casualty effectsranging from harassment to incapacitation to death. Some particulareffects produced by such toxic chemical agents can be choking, bloodpoisoning, lacrimation, nerve poisoning, laxation, and various forms ofmental and physical disorganization and disorientation. In the eventthat decontamination cannot be properly handled by natural processessuch as wind, rain, dew, sunlight, heat and actinic rays from the sun,some form of chemical decontamination must be employed.

Typical of the prior art systems for decontamination are the use ofpowders such as carbon, fuller's earth, bentonite, and other polymersystems; and solutions of bleach, various solvents, and variousemulsions, which are sprayed or wiped over the contaminated surfaceswith an applicator. Such methods suffer from the disadvantage that thesolutions are corrosive and in many cases toxic. Further, there is aneed for water which is not always convenient. These prior arttechniques are generally not suited for indoor use on interiors, and aredifficult to employ in low temperature regions of the country. Thepowders are also ineffective against toxic chemical agents when theagents are in their thickened form.

Thus, it should be apparent that there exists a need for a radicallydifferent and effective decontaminating agent for decontaminatingvarious surfaces subject to toxic chemical agent contamination. Thepresent invention fulfils such a need and provides a new decontaminatingsystem which has a reduced toxic effect, does not depend on the use ofwater in order to function, and is capable of use at low temperatures.While cellular polymeric materials are not new to chemical warfare asindicated in U.S. Pat. No. 4,708,869, issued Nov. 24, 1987, the porouscopolymeric powders of the present invention are employed to function asa vehicle for the decontaminating agent rather than for the toxicchemical agent as in the '869 patent.

SUMMARY OF THE INVENTION

This invention relates to a process of decontaminating a surfacecontaminated with a toxic chemical agent in which there is applied tothe contaminated surface, a macroporous cross-linked hydrophobiccopolymer containing an agent which is a decontaminant for the toxicchemical agent present on the surface. The decontaminant can be achemical neutralizer such as sodium hydroxide; lithium hydroxide;concentrated or supertropical bleach; mixtures of diethylene triamine,2-methoxy ethanol, and sodium hydroxide; and other solvents or emulsionbased mixtures.

One monomer of the copolymer is a monounsaturated monomer such as laurylmethacrylate, and the other monomer of the copolymer is apolyunsaturated monomer such as ethylene glycol dimethacrylate. Thecopolymer can also be formed using only polyunsaturated monomers. Thecopolymer is in the form of a powder and the powder is a combined systemof particles. The system of powder particles includes unit particles ofless than about one micron in average diameter, agglomerates of fusedunit particles of sizes in the range of about twenty to eighty micronsin average diameter, and aggregates of clusters of fused agglomerates ofsizes in the range of about two hundred to about twelve hundred micronsin average diameter.

The invention also relates to an adsorbent for deoontaminating toxicchemical agents in which a macroporous cross-linked hydrophobiccopolymer is produced by precipitation polymerization in a solvent of atleast one monounsaturated monomer and at least one polyunsaturatedmonomer soluble therein, or only polyunsaturated monomers, and adecontaminating agent is entrapped within the copolymer.

Further, the invention relates to a process of removing toxic chemicalagents from a surface contaminated with the toxic chemical agent inwhich there is applied to the contaminated surface, a macroporouscross-linked hydrophobic copolymer, adsorbing the toxic chemical agentinto the copolymer, and removing the copolymer along with the adsorbedtoxic chemical agent from the contaminated surface.

A precipitation polymerization process is used for producing themacroporous cross-linked copolymer. In the process, there iscopolymerized at least one monounsaturated monomer and at least onepolyunsaturated monomer in the presence of an organic liquid which is asolvent for the monomers but not for the copolymer. The process can alsobe conducted using only polyunsaturated monomers. The copolymerizationof the monomers is initiated by means of a free radical generatingcatalytic compound, precipitating a copolymer in the solvent in the formof a powder. A dry powder is formed by removing the solvent from theprecipitated copolymeric powder.

Several suitable monomers are disclosed in U.S. Pat. No. 4,724,240. Themonounsaturated monomer can also be vinyl pyrrolidone, diacetoneacrylamide, or 2-phenoxyethyl methacrylate. The polyunsaturated monomercan be ethylene glycol dimethacrylate or tetraethylene glycoldimethacrylate. The solvent is preferably isopropyl alcohol, althoughethanol, toluene, heptane, and cyclohexane, may also be employed.

The monounsaturated monomer and the polyunsaturated monomer can bepresent in mol ratios of, for example, 20:80, 30:70, 40:60, or 50:50.The process may include the step of stirring the monomers, solvent, andthe free radical generating catalytic compound, during copolymerization.Preferably, the dry powder is formed by filtering excess solvent fromthe precipitated powder, and the filtered powder is vacuum dried. Thepowder may then be "post adsorbed" with various decontaminatingmaterials.

The powders of the present invention may also be used as carriers oradsorbents for materials such as water, aqueous systems, emollients,moisturizers, fragrances, dyes, pigments, flavors, drugs such asibuprofen, phosphoric acid, insect repellents, vitamins, sunscreens,detergents, cosmetics, pesticides, pheromones, herbicides, steroids,sweeteners, pharmaceuticals, and antimicrobial agents. Finely dividedsolids such as analgesic materials can be adsorbed by dissolving thefinely divided analgesic in a solvent, mixing the analgesic and solventwith the powder, and removing the solvent. Other post adsorbablematerials include alkanes, alcohols, acid esters, silicones, glycols,organic acids, waxes, and alcohol ethers.

These and other objects, features, and advantages, of the presentinvention will become apparent when considered in light of the followingdetailed description, including the accompanying drawings.

IN THE DRAWlNGS

FIG. 1 is a photomicrograph of the various components of the complexstructure of the powder produced in Example I and including unitparticles, agglomeratures, and aggregates.

FIGS. 2 and 3 are photomicrographs of the agglomerates and aggregates ofFIG. 1, respectively, shown on a larger scale.

FIG. 4 is a photomicrograph of a polymer bead produced by suspensionpolymerization.

FIG. 5 is a photomicrograph of the bead of FIG. 4 with a portion of theshell removed to reveal the interior structure of the bead.

FIG. 6 is a photomicrograph of a hydrophobic copolymeric powdermaterial. The powder is shown in magnification as it appears when theagitation gate employed in the process for producing the hydrophobicpowder is zero rpm.

FIGS. 7-10 are additional photomicrographs of hydrophobic copolymericpowder materials. The powder is shown in magnification as it appearswhen the agitation rate employed in the process for producing thehydrophobic powder varies from seventy-five rpm up to eight hundred rpm.

In the above figures in the drawing, the magnification is indicated ineach instance. For example, the magnification in FIGS. 6-9 is 1000 X,and 2000 X in FIG. 10. FIGS. 6-10 also include an insert identifying alength approximating ten microns for comparative purposes.

It should be pointed out, that in viewing the various figures, one willnote that as the rate of stirring is increased from zero rpm up to eighthundred rpm, that the size of the unit particles increase. This is indirect opposition to what has been traditionally observed in suspensionpolymerization systems, wherein increases in stirring rates decreaseparticle size. Because of the increased size of the unit particles shownin FIG. 10 and the resulting decrease in surface area, the adsorptivecapacity of these large particles is less than the adsorptive capacityof the smaller sized particles shown in FIGS. 6-9.

The most effective unit particles can be produced if the rate ofstirring is maintained below about three hundred rpm, although particlesproduced at rates beyond three hundred rpm are useful and adsorptive,but to a lesser extent.

DETAILED DESCRIPTION OF THE INVENTION

The material of the present invention, can be broadly and generallydescribed as a crosslinked copolymer capable of entrapping solids,liquids, and gases. The copolymer is in particulate form and constitutesfree flowing discrete solid particles even when loaded with an activematerial. When loaded, it may contain a predetermined quantity of theactive material. One copolymer of the invention has the structuralformula: ##STR1## where the ratio of x to y is 80:20, R' is --CH₂ CH₂--, and R" is --(CH₂)₁₁ CH₃.

The copolymer is a highly crosslinked copolymer, as evidenced by theforegoing structural formula, and is more particularly a highlycrosslinked polymethacrylate copolymer. This material is manufactured bythe Dow Corning Corporation, Midland, Mich., U.S.A., and sold under thetrademark POLYTRAP®. It is a low density, highly porous, free-flowingwhite particulate, and the particles are capable of adsorbing highlevels of lipophilic liquids and some hydrophilic liquids, while at thesame time maintaining a free-flowing particulate character.

In the powder form, the structure of the particulate is complex, andconsists of unit particles less than one micron in average diameter. Theunit particles are fused into agglomerates of twenty to eighty micronsin average diameter. These agglomerates are loosely clustered intomacro-particles termed aggregates of about 200 to about 1200 microns inaverage diameter.

Adsorption of actives to form "post adsorbed" powder, can beaccomplished using a stainless steel mixing bowl and a spoon, whereinthe active ingredient is added to the empty dry powder, and the spoon isused to gently fold the active into the powder. Low viscosity fluids maybe adsorbed by addition of the fluids to a sealable vessel containingthe powder and tumbling the materials until consistency is achieved.More elaborate blending equipment such as ribbon or twin cone blenderscan also be employed.

The following example illustrates the method for making a post adsorbentpowder, of the type illustrated in FIGS. 1-3 and 6-10.

EXAMPLE I

A hydrophobic porous copolymer was produced by the precipitationpolymerization technique by mixing in a five hundred milliliterpolymerization reactor equipped with a paddle type stirrer, 13.63 gramsof ethylene glycol dimethacrylate monomer, or eighty mole percent, and4.37 grams of lauryl methacrylate monomer, or twenty mole percent.Isopropyl alcohol was added to the reactor as the solvent in the amountof 282 grams. The monomers were soluble in the solvent, but not theprecipitated copolymer. U.S. Pat. No. 4,724,240 lists other monomerswhich may also be employed. The process can be conducted with onlypolyunsaturated monomers if desired. Other solvents that can be employedare ethanol, toluene, cyclohexane, or heptane. The mixture includingmonomers, solvent, and 0.36 grams of catalytic initiator benzoylperoxide, was purged with nitrogen. The system was heated by a waterbath to about sixty degrees Centigrade until copolymerization wasinitiated, at which time, the temperature was increased to about 70-75degrees Centigrade for six hours, in order to complete thecopolymerization. During this time, the copolymer precipitated from thesolution. The copolymerization produced unit particles of a diameterless than about one micron. Some of the unit particles adhered togetherproviding agglomerates of the order of magnitude of about twenty toeighty microns in diameter. Some of the agglomerates adhered further andwere fused and welded one to another, forming aggregates of loosely heldassemblies of agglomerates of the order of magnitude of about two toeight hundred microns in diameter. The mixture was filtered to removeexcess solvent, and a wet powder cake was tray dried in a vacuum oven. Adry hydrophobic copolymeric powder consisting of unit particles,agglomerates, and aggregates was isolated.

The adsorptive capacity of the hydrophobic particulates produced inExample I, as a function of the stirring rate, was determined. Thestirring rate during the reaction in Example I significantly influencesthe adsorption properties of the particulate materials. The adsorptivityof the particulate materials decreases with an increase in stirringrate, and the density of the particulates increases. These results aretabulated and set forth in Tables I-III.

                  TABLE I                                                         ______________________________________                                               Bulk     Aggre-  Agglom-                                               Agitation                                                                            Density  gate    erate  Unit                                           Rate   Size     Size    Size   Particle                                                                             Adsorption                              (RPM)  (g/cc)   (μ)  (μ) Size (μ)                                                                          Capacity*                               ______________________________________                                         0     0.067    182.5   33.9   1.0    83.0                                     75    0.077    140.6   36.6   0.5    84.8                                    150    0.071    149.8   39.8   0.8    83.0                                    300    0.293     47.0   34.0   1.5-2.0                                                                              58.3                                    800    0.440    --      10.0   3.0-5.0                                                                              37.7                                    ______________________________________                                         *Percent Silicone Oil                                                    

                  TABLE II                                                        ______________________________________                                        Stirring Adsorption Capacity %                                                Speed              Mineral            Organic                                 RPM      Water     Oil      Glycerine Ester*                                  ______________________________________                                         0       0         80       75        80                                       75      0         83.9     75        81.5                                    150      0         80       75        80                                      300      0         54.5     58.3      54.5                                    ______________________________________                                         *2-ethylhexyl-oxystearate                                                

                  TABLE III                                                       ______________________________________                                        Adsorption Capacity %                                                         Mineral     2-ethylhexyl                                                                             Silicone  Density (g/cm.sup.3)                         RPM    Oil      oxystearate                                                                              Oil     Bulk  Tapped                               ______________________________________                                         0     82.5     82.5       86.5    0.0368                                                                              0.0580                                75    82.3     82.2       86.5    0.0462                                                                              0.0667                               150    82.3     82.3       86.3    0.0527                                                                              0.0737                               200    81.5     81.5       85.7    0.0554                                                                              0.0752                               250    79.2     80.0       84.8    0.0636                                                                              0.0859                               300    68.8     68.8       75.0    0.1300                                                                              0.1768                               450    58.3     58.3       61.5    0.1736                                                                              0.2392                               600    54.5     54.5       60      0.1933                                                                              0.2792                               700    42.2     42.5       45.7    0.2778                                                                              0.4142                               800    33.3     28.6       33.3    0.3862                                                                              0.5322                               1000   32.8     28.5       32.9    0.3808                                                                              0.5261                               ______________________________________                                    

In the foregoing tables, it can be seen that adsorption and density, asa function of stirring rate, was determined for several fluids includinga silicone oil, water, mineral oil, glycerine, and an organic ester.From zero rpm up to about 250 rpm, the adsorptivity of the porouscopolymeric powder particulates of Example I remained essentiallyconsistent. However, at about three hundred rpm, there was a substantialdecrease in adsorptivity, which decrease became more apparent as thestirring rate was increased up to about one thousand rpm. A similarpattern is evidenced by the data which are reflective of the density.

This phenomenon is more apparent in the photomicrographic figures of thedrawing. Thus, it can be seen from FIG. 6, that the particle size of theunit particles increases as the stirring rate is increased, as evidencedby FIG. 10. A progression in this phenomenon can be observed in FIGS.7-9.

While the procedure of Example I is a precipitation polymerizationprocess and not a suspension polymerization system, the prior artdealing with both "in situ" and "post adsorbed" categories of suspensionpolymerization processes, teaches that an increase in stirring ratecauses a decrease in particle size. This is documented, for example, inU.S. Pat. No. 4,224,415, issued Sept. 23, 1980, and in the PCTInternational Publication. The PCT International Publication employsstirring rates upwards of nine hundred to twelve hundred rpm. In ExampleI of the present invention, however, increases in stirring rates notonly do not decrease the particle size, but in fact have exactly theopposite effect, causing the unit particle size to increase. As the rateof stirring is increased from zero rpm up to one thousand, the densityof the particles increases and the adsorptive capacity decreases.

In accordance with the above, it should be apparent that it is possibleto tailor porous adsorbent powders of a particular particle size andadsorptivity by means of stirring rate. Thus, with large unit particlesin FIG. 10, the adsorptive capacity is less than the adsorptive capacityof smaller sized unit particles in FIGS. 6-9. While the most effectiveparticles are produced when the rate of stirring is maintained belowabout three hundred rpm, particles produced at rates beyond threehundred rpm are useful.

It is important to understand that the method of Example I for theproduction of hydrophobic porous copolymeric particulate powdermaterials is characterized as a precipitation polymerization technique.In accordance with this technique, monomers are dissolved in acompatible volatile solvent in which both monomers are soluble. Polymerin the form of a powder is precipitated and the polymer is insoluble inthe solvent. No surfactant or dispersing aid is required. The materialsproduced are powders and not spheres or beads. The powder particulatesinclude unit particles, agglomerates, and aggregates. The volatilesolvent is subsequently removed resulting in a dry powder, which can bepost adsorbed with a variety of functional active ingredients. Thesuspension polymerization process on the other hand, provides thatpolymerization be carried out in water, and in some cases chloroform orchlorinated solvents. The monomers, the active, and the catalyst, formbeads or droplets in water, and polymerization occurs within each bead.A surfactant or stabilizer, such as polyvinyl pyrrolidone, is requiredin order to prevent the individually formed beads and droplets fromcoalescing. The resulting beads, with the active material entrappedtherein, include a substantially spherical outer crust or shell, theinterior of which contains a macroporous structure of fused unitparticles, agglomerates, and aggregates. The bead is ten microns indiameter to one hundred-fifty microns, depending upon the rate ofagitation employed during the process. Such beads are shown in FIGS. 4and 5.

Some unique features of the powders of Example I and FIGS. 1-3 and 6-10are their ability to adsorb from sixty to eighty percent of a liquid andyet remain free flowing. The materials provide a regulated release ofvolatile ingredients such as cyclomethicone entrapped therein, and havethe capability of functioning as carriers for other non-volatile oils.Loaded powders disappear when rubbed upon a surface. This phenomenon isbelieved due to the fact that large aggregates of the material scatterlight rendering the appearance of a white particulate, however, uponrubbing, these large aggregates decrease in size approaching the rangeof visible light and hence seem to disappear. The materials findapplications in diverse areas such as cosmetics and toiletries,household and industrial products, pesticides, pheromone carriers, andpharmaceuticals. The materials do not swell in common solvents and arecapable of physically adsorbing active ingredients by the filling ofinterstitial voids by capillary action. The active ingredients aresubsequently released by capillary action or wicking from the voidswithin the particulates.

In Examples II-IV, the hydrophobic powder material produced in ExampleI, was surface treated in order to render the hydrophobic powder morehydrophilic. A first method is shown in Example II. A second method isset forth in Example III. Example IV describes an additional step thatmay be included in the method of Example III. References to hydrophobicpowder in Examples II-IV refers to the powder material produced inaccordance with Example I.

EXAMPLE II

5.0 grams of hydrophobic powder was refluxed and stirred with 10.0 gramsof NaOH, 150 cc of butyl alcohol, and 15 cc of water. After reflux for4.5 hours, the product was filtered and washed four times with 100 cc of1:1 isopropyl alcohol and water, once with butyl alcohol, and once againwith isopropyl alcohol. The powder was vacuum dried to constant weight.Scanning electron microscopic photomicrographs of the treated powdershowed no visible change in aggregate structure compared to untreatedpowder. Electron spectroscopic analysis (ESCA) showed 6 atom % Na at thesurface of the powder. Attenuated total reflectance infrared radiationanalysis indicated the presence of carboxylate ion (1590 cm-1) in thetreated powder. The treated powder was easily wetted by water andproduced a viscous paste upon minimal mixing. By comparison, untreatedpowder was completely non-wetted by water.

EXAMPLE III

2.5 grams of methacrylic acid was added to 25.0 grams of hydrophobicpowder that had been suspended in a mixture of 100 cc toluene, 400 ccheptane, and 0.275 grams 1,1'-azobiscyclohexanecarbonitrile. The mixturewas flushed with N₂ and heated at reflux (104° C.) for 4 hours. Theproduct was filtered, washed with isopropyl alcohol, and dried undervacuum to a constant weight. Scanning electron microscopicphotomicrographs of the powder showed no apparent change in aggregatestructure. Electron spectroscopic analysis (ESCA) showed an enrichmentof oxygen (26.4 atom % 0) at the surface of the powder compared tountreated powder (20.0 atom % 0). The product was wettable by water.

EXAMPLE IV

5.0 grams of product from Example III was mixed with 2.0 grams NaOHdissolved in a mixture of 200 cc isopropyl alcohol and 50 cc water. Themixture was stirred for 10 minutes at 65° C. The powder was recovered byfiltration, washed twice with 300 cc 1:1 isopropyl alcohol H₂ O, anddried under vacuum to a constant weight. Electron spectroscopic analysis(ESCA) showed the presence of 3.4 atom % Na on the surface of thepowder. The powder was highly adsorbent toward water.

Test data showing the hydrophilic nature of the materials produced bythe methods of Examples II-IV are set forth in Table IV. It should beapparent from Table IV that the powder materials produced by both themethod of Example 11 and the method of Examples IlI-IV are capable ofadsorbing water, in contrast to the hydrophobic powder of Example I. Infact, Table II shows that the hydrophobic powders produced by Example Idid not adsorb water to any extent.

In Example II, the powder of Example I was saponified by reacting thesurface with an aqueous alkali, rendering the hydrophobic nature of thepowder surface after saponification to be more hydrophilic. Potassiumhydroxide and quaternary ammonium hydroxides may also be employed. InExample III, alteration of the surface characteristics of the powder wasachieved by polymerizing an acrylate monomer on the surface of thehydrophobic powder in order to form hydrophilic carboxylic acid sitesthereon. Another suitable monomer is acrylic acid. The carboxylic acidsites may be further converted to more hydrophilic carboxylate anions inExample IV, by reacting the powder surface containing the carboxylicacid sites with aqueous alkali.

Free flowing adsorption capacity of the surface modified powders ofExamples II-IV was determined by addition of incremental amounts ofliquid to a known amount of powder, using gentle mixing, until thepowder was no longer free flowing. The capacity is shown in Table IV andwas expressed as: ##EQU1##

                  TABLE IV                                                        ______________________________________                                        Maximum Free Flowing Adsorption Capacity (%)                                                      Mineral                                                   Sample       H.sub.2 O                                                                            Oil       Ester*                                                                              Silicone**                                ______________________________________                                        Untreated Powder                                                                           0      77.3      78.3  78.3                                      Control of                                                                    Example I                                                                     Powder of    69.8   50.4      51.2  56.0                                      Example II                                                                    Saponified                                                                    With NaOH                                                                     Powder of    74.5   75.6      72.3  76.9                                      Example III                                                                   Powder of    73.0   72.3      73.0  76.2                                      Example IV                                                                    ______________________________________                                         *2-ethylhexyl oxstearate                                                      **Octamethylcyclotetrasiloxane                                           

EXAMPLE V

Example I was repeated, except that different monomer systems wereemployed and at varying mol ratios of the monomers. The copolymericpowders produced were tested for their adsorptive capacity for variouslipophilic fluids and for water. The monomer pairs employed, the molratios, and the adsorption data generated for each monomer pair, areshown in Table V. It will be noted that the powders produced from themonomer pairs of Example V not only were capable of adsorbingsubstantial quantities of lipophilic fluids, but that water was capableof being adsorbed. This is in contrast to Example I and Table II whereno water was adsorbed.

Example V sets forth the concept of the providing hydrophilic-lipophiliccopolymeric powders capable of adsorbing water and lipophilic fluids. Bya careful selection of monomers, there can be produced adsorbent powderpossessing more versatility than the hydrophobic powder of Example I. Inaddition, the method of Example V is a viable alternative to the surfacetreatment methods of Examples II-IV, and provides powder materials ofsubstantially equivalent utility.

                                      TABLE V                                     __________________________________________________________________________                   Absorption Per Cent                                                           Mole                                                                              2-Ethylhexyl                                                                         Mineral                                             Monomers       Ratio                                                                             Oxystearate                                                                          Oil  Glycerine                                                                           Water                                    __________________________________________________________________________    Vinyl pyrrolidone*                                                                           20  77     74   80    70                                       Ethylene glycol                                                                              80                                                             dimethacrylate**                                                              Diacetone acrylamide*                                                                        20  68     75   73    75                                       Ethylene glycol                                                                              80                                                             dimethacrylate**                                                              Diacetone acrylamide*                                                                        30  68     66   73    72                                       Ethylene glycol                                                                              70                                                             dimethacrylate**                                                              2 Phenoxyethyl methacrylate**                                                                40  68     64   72    68                                       Tetraethylene glycol                                                                         60                                                             dimethacrylate*                                                               2 Phenoxyethyl methacrylate**                                                                50  60     60   70    70                                       Tetraethylene glycol                                                                         50                                                             dimethyacrylate*                                                              __________________________________________________________________________     *Hydrophilic                                                                  **Lipophilic                                                             

The water adsorbing porous polymeric materials of Examples II-V are tobe contrasted with the water containing beads of U.S. Pat. No.3,627,708, issued Dec. 14, 1971. The bead of the '708 patent is producedby "in situ" suspension polymerization, and is adapted to contain wateronly because of the presence of a solubilizer such as sodium bis(2-ethylhexyl) sulfosuccinate. The material of Examples II-V, on the other hand,is produced by a precipitation polymerization process, which contains nosolubilizer, and produces a material in the form of a powder consistingof unit particles, agglomerates, and aggregates. Thus, these materialsare very distinct from the materials of the '708 patent.

In order to demonstrate the use of the powder material of Example I asan adsorbent for the decontamination of toxic chemical agents, twosimulated toxic chemical agents were employed. The first simulated toxicchemical agent was dimethyl methyl phosphonate (DMMP) or CH₃P(O)(OCH₃)₂, and the second simulated toxic chemical agent was methylsalicylate (MS) or C₆ H₄ OHCOOCH₃. Both simulated chemical agentspossess physical properties resembling most toxic chemical agents, andMS in particular, has properties much the same as mustard blisteragents. The simulated chemical agents DMMP and MS were thickened tofurther assimilate viscous nature of toxic chemical agents by employingfour percent by weight of polymethylmethacrylate polymer powder K-125manufactured by Rohm and Haas Company, Philadelphia, Pa.

The function of the copolymeric porous powder of Example I is twofold.The first function of the dry empty powder is to directly adsorb toxicchemical agents when it is applied to such surfaces as skin, clothing,and equipment and to thereby physically remove the toxic chemical agentfrom the surface which is contaminated. The second function of thecopolymeric porous powder of Example I is to function as a carrier anddelivery mechanism for a decontaminating agent. In the second function,the decontaminating agent is post adsorbed onto the powder of Example I.The loaded or post adsorbed powder is brought into direct contact with asurface contaminated with a toxic chemical agent. Upon adsorbing thetoxic chemical agent, the decontaminating material reacts with andneutralizes or renders ineffective the toxic chemical agent present onthe surface. Both functions of the copolymeric porous powder of ExampleI are shown below in Example VI and in Example VII.

EXAMPLE VI

A twenty-five percent sodium hydroxide solution was used as thedecontaminating agent. With the aid of a wetting agent, it wasdetermined that up to sixty-six percent by weight of the decontaminatingagent could be post adsorbed on the powder of Example I. The wettingagent employed was an amphoteric surfactant. The surfactant was asubstituted imidazoline manufactured by Mona Industries, Inc., Paterson,N.J., and sold under the trademark MONATERICS®. Each of MONATERICS® 811,985A, and 1000, were adequate in aiding the adsorption of thetwenty-five percent sodium hydroxide decontaminating agent on the powderof Example I, to levels approaching sixty-six percent by weight based onthe total weight of the post adsorbed powder. As an aternative to theuse of a wetting agent, the surface treated powders of Examples II-IVcould be employed, as well as the specialty powders of Example V, any ofwhich are more hydrophilic than the hydrophobic powder of Example I. Inany event, a fifty percent loading of the twenty-five percent sodiumhydroxide decontaminating agent on the powder of Example I was selected,and a post adsorbed powder containing the decontaminating agent wasprepared using each of the three Monateric® surfactants. These preloadedpost adsorbed powders still adsorbed up to a loading of 75% of either MSor DMMP.

The decontaminating powder was evaluated along with six otherconventional powder materials and the capacity of the seven powders foradsorbing DMMP and MS was determined. The results for the adsorption ofDMMP are tabulated in Table VI which indicates that the performance ofthe post adsorbed powder of Example I exceeded the performance of theother six powder materials. The percentages indicated in Table VI arebased on the weight of the powder in each instance. Table VII shows thetime required for a predetermined quantity of each of the seven powdersof Table VI to adsorb a predetermined quantity of DMMP.

EXAMPLE VII

The empty powder of Example I was sprinkled on glass plates eachcontaining the thickened simulated chemical agents DMMP and MS. Thepowder and the simulated chemical agent were not further mixed orintermingled. After allowing a brief time for the powder to adsorb thesimulated chemical agent, a compressed air stream was directed at eachof the plates. In each case, the thickened simulated chemical agent wasremoved from the glass plate, indicating the ability of the powder ofExample I to physically decontaminate surfaces. Similar results wereobtained on metal and on painted metal surfaces.

                  TABLE VI                                                        ______________________________________                                        ADSORPTION CAPACITY FOR DMMP.sup.a                                            Adsorbent        % Free Flowing.sup.b                                                                        % Total                                        ______________________________________                                        A.   Powder of       83.3          89.8                                            Example I                                                                B.   Polymeric Powder of                                                                           78.3          86.5                                            Methacryloxypropyl                                                            Trimethoxy Silane                                                        C.   Acetic Acid Treated                                                                           82.8          87.1                                            Powder of B                                                              D.   Methacrylate    77.3          84.5                                            Polymeric Powder                                                         E.   Activated Carbon                                                                              54.6          69.9                                       F.   Fuller's Earth (RVM)                                                                          56.5          68.3                                       G.   Fuller's Earth (LVM)                                                                          54.5          66.5                                       ______________________________________                                         .sup.a Dimethyl Methyl Phosphonate                                            .sup.b Amount adsorbed to maintain free flowing character of adsorbent        particulate                                                              

                  TABLE VII                                                       ______________________________________                                        ADSORPTION RATE OF DMMP.sup.a                                                                                Time to Capillary                                             g Ad-   g       Elevation of 72 MM                             Adsorbent      sorbent Agent.sup.a                                                                           (hrs. - min.)                                  ______________________________________                                        A.  Powder of      0.1525  1.3482                                                                              2-10                                             Example I                                                                 B.  Polymeric Powder of                                                                          0.1509  0.9661                                                                              1-10                                             Methacryloxypropyl                                                            Trimethoxy Silane                                                         C.  Acetic Acid Treated                                                                          0.0822  0.5529                                                                              1-50                                             Powder of B                                                               D.  Methacrylate   0.2290  1.2477                                                                              4-5                                              Polymeric Powder                                                          E.  Activated Carbon                                                                             0.4614  1.0690                                                                              4-30                                         F.  Fuller's Earth (RVM)                                                                         0.3052  0.6586                                                                              4-50                                         G.  Fuller's Earth (LVM)                                                                         0.3695  0.7335                                                                              5-10                                         ______________________________________                                         .sup.a Dimethyl Methyl Phosphonate                                       

In light of Examples VI-VII and Tables VI-VII, it is believed that thepowder materials of the present are of general utility asdecontaminating agents, and would be effective against most toxicchemical agents. Representative of toxic chemical agents which could beneutralized are choking agents such as phosgene, diphosgene, andchlorine; blood agents such as hydrogen cyanide, cyanogen chloride, andarsine; vomiting agents such as Adamsite and diphenylchloroarsine; nerveagents such as Tabun which is ethyl phosphoro-dimethylamidocyanidate,Sarin which is isopropyl methylphosphonofluoridate, Soman which ispinacolyl methylphosphonofluoridate, and V-agents such as VX; blisteragents such as distilled mustard, nitrogen mustards, Lewisite, andarsine derivatives; tear agents and incapacitating agents such as BZwhich is 3-quinuclidinyl benzilate. The adsorbent copolymeric powder ofthe present invention can be used to decontaminate such toxic chemicalagents occurring on most surfaces including, for example, masks,clothing, gloves, boots, skin, shelters, hardware, equipment, andbuilding interiors.

It will be apparent from the foregoing that many other variations andmodifications may be made in the structures, compounds, compositions,and methods described herein without departing substantially from theessential features and concepts of the present invention. Accordingly,it should be clearly understood that the forms of the inventiondescribed herein are exemplary only and are not intended as limitationson the scope of the present invention.

That which is claimed is:
 1. A process of decontaminating a surfacecontaminated with a toxic chemical comprising entrapping an agent whichis a decontaminant for the toxic chemical present on the surface withininterstitial voids of a macroporous crosslinked hydrophobic polymerpowder, the powder including unit particles, agglomerates, andaggregates, applying the powder to the contaminated surface, adsorbingthe toxic chemical into the interstitial voids of the powder,neutralizing the toxic chemical with the decontaminating agent presentin the voids, and removing the powder from the surface.
 2. The processof claim 1 wherein the decontaminant is a chemical neutralizer selectedfrom the group consisting of sodium hydroxide, lithium hydroxide,concentrated bleach, and a mixture of diethylene triamine, 2-methoxyethanol, and sodium hydroxide.
 3. The process of claim 1 in which thepowder is a combined system of particles, the system of powder particlesincluding unit particles of less than about one micron in averagediameter, agglomerates of fused unit particles of sizes in the range ofabout twenty to eighty microns in average diameter, and aggregates ofclusters of fused agglomerates of sizes in the range of about twohundred to about twelve hundred microns in average diameter.
 4. Theprocess of claim 1 in which the polymer is formed by copolymerizinglauryl methacrylate and ethylene glycol dimethacrylate.
 5. A process ofremoving a toxic chemical from a surface contaminated with the toxicchemical comprising preparing a macroporous crosslinked hydrophobicpolymer having interstitial voids which are empty and free of activeingredients, applying the empty macroporous polymer to the contaminatedsurface, adsorbing the toxic chemical into the interstitial voids of theempty powder, and removing the powder along with the adsorbed toxicchemical from the contaminated surface.
 6. The process of claim 5 inwhich the powder is a combined system of particles, the system of powderparticles including unit particles of less than about one micron inaverage diameter, agglomerates of fused unit particles of sizes in therange of about twenty to eighty microns in average diameter, andaggregates of clusters of fused agglomerates of sizes in the range ofabout two hundred to about twelve hundred microns in average diameter.7. The process of claim 5 wherein the adsorbed toxic chemical isselected from the group consisting of choking agents, blood agents,vomiting agents, nerve agents, blister agents, tear agents, andincapacitating agents.
 8. The process of claim 5 wherein the adsorbedtoxic chemical is selected from the group consisting of phosgene,diphosgene, chlorine, hydrogen cyonide, cyanogen chloride, arsine,Adamsite, diphenylchloroarsine, ethyl phosphoro-dimethylamidocyanidate,isopropyl methylphosphonofluoridate, pinacolylmethylphosphonofluoridate, VX, distilled mustard, nitrogen mustard,Lewisite, arsine derivatives, and 3-quinuclidinyl benzilate.
 9. Theprocess of claim 5 in which the polymer is formed by copolymerizinglauryl methacrylate and ethylene glycol dimethacrylate.